A novel image retrieval approach based on color features and anisotropic directional information is proposed for content based image retrieval systems （CBIR）. The color feature is described by the color histogram ...A novel image retrieval approach based on color features and anisotropic directional information is proposed for content based image retrieval systems （CBIR）. The color feature is described by the color histogram （CH）, which is translation and rotation invariant. However, the CH does not contain spatial information which is very important for the image retrieval. To overcome this shortcoming, the subband energy of the lifting directionlet transform （L-DT） is proposed to describe the directional information, in which L-DT is characterized by multi-direction and anisotropic basis functions compared with the wavelet transform. A global similarity measure is designed to implement the fusion of both color feature and anisotropic directionality for the retrieval process. The retrieval experiments using a set of COREL images demonstrate that the higher query precision and better visual effect can be achieved.展开更多
In order to improve the bit allocation efficiency of Directionlet coding,a modified Breiman,Friedman,Olshen and Stone(BFOS) algorithm is suggested for rate consistent truncation.Two modifications are:(1) Dominant dire...In order to improve the bit allocation efficiency of Directionlet coding,a modified Breiman,Friedman,Olshen and Stone(BFOS) algorithm is suggested for rate consistent truncation.Two modifications are:(1) Dominant direction adjustment is proposed to balance the cost of sparse description and segment artifacts caused by discontinuous adjacent direction pairs.(2) Priority related merging is also proposed in the BFOS distortion list to find an optimal trimming element for unequal-importance bit allocation.Experimental results show that block effects could be removed without obvious bpp increment by selecting the dominant direction and its adjustment according to neighborhood homogeneity,and combined multi-PRIority(PRI) based merging of the M-ordered list offers unequal importance allocation and leads to a Peak Signal-to-Noise Ratio(PSNR) gain of 0.4 dB～1.3 dB.展开更多
基金supported by the National High Technology Research and Development Program of China (863 Program) (2007AA12Z1362007AA12Z223)+2 种基金the National Basic Research Program of China (973Program) (2006CB705707)the National Natural Science Foundation of China (60672126, 60607010)the Program for Cheung Kong Scholars and Innovative Research Team in University (IRT0645)
文摘A novel image retrieval approach based on color features and anisotropic directional information is proposed for content based image retrieval systems （CBIR）. The color feature is described by the color histogram （CH）, which is translation and rotation invariant. However, the CH does not contain spatial information which is very important for the image retrieval. To overcome this shortcoming, the subband energy of the lifting directionlet transform （L-DT） is proposed to describe the directional information, in which L-DT is characterized by multi-direction and anisotropic basis functions compared with the wavelet transform. A global similarity measure is designed to implement the fusion of both color feature and anisotropic directionality for the retrieval process. The retrieval experiments using a set of COREL images demonstrate that the higher query precision and better visual effect can be achieved.
基金Supported by The National Natural Science Foundation of China (No.60972133)Guangzhou Natural Science Foundation Team Project (No.9351064101000003 & 8451008901000615)
文摘In order to improve the bit allocation efficiency of Directionlet coding,a modified Breiman,Friedman,Olshen and Stone(BFOS) algorithm is suggested for rate consistent truncation.Two modifications are:(1) Dominant direction adjustment is proposed to balance the cost of sparse description and segment artifacts caused by discontinuous adjacent direction pairs.(2) Priority related merging is also proposed in the BFOS distortion list to find an optimal trimming element for unequal-importance bit allocation.Experimental results show that block effects could be removed without obvious bpp increment by selecting the dominant direction and its adjustment according to neighborhood homogeneity,and combined multi-PRIority(PRI) based merging of the M-ordered list offers unequal importance allocation and leads to a Peak Signal-to-Noise Ratio(PSNR) gain of 0.4 dB～1.3 dB.
